Here's a link that might be of interest. As was mentioned earlier in this thread (and all other threads of people wanting new packs in bundles), they do take anywhere from a few days to a few weeks to be added to a bundle.
EA's help page on bundles:
https://help.ea.com/en/help/the-sims/the-sims-4/the-sims-4-build-a-bundle/
In the help page it says that if there is a sims sale on currently, then any packs that are NOT on sale will not be available in the bundle. This is the case currently, as there is a sims sale and dream home decorator is NOT included in the current sale (and so will not be available to bundle). This might be a new feature.
I am hoping that it will be available shortly after the sale (as that would line up with normal timelines for including packs in the bundles).
From my short research, I found that University was available to bundle almost immediately (as soon as it was released worldwide), Eco lifestyle took 2 weeks, and snowy escape was about 2.5 weeks. Use this data to estimate the time as you please (a good guess would either to take the average/upper bound, or to see it as a trend of taking longer and longer each pack - it's up to you).
I hope this helps!